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Iwona Kochanska - One of the best experts on this subject based on the ideXlab platform.

  • assessment of wide sense stationarity of an underwater acoustic channel based on a pseudo random binary sequence Probe Signal
    Applied Sciences, 2020
    Co-Authors: Iwona Kochanska
    Abstract:

    The performances of Underwater Acoustic Communication (UAC) systems are strongly related to the specific propagation conditions of the underwater channel. Designing the physical layer of a reliable data transmission system requires a knowledge of channel characteristics in terms of the specific parameters of the stochastic model. The Wide-Sense Stationary Uncorrelated Scattering (WSSUS) assumption simplifies the stochastic description of the channel, and thus the estimation of its transmission parameters. However, shallow underwater channels may not meet the WSSUS assumption. This paper proposes a method for testing the Wide-Sense Stationary (WSS) part of the WSSUS feature of a UAC channel on the basis of the complex envelope of a received Probe Pseudo-Random Binary Sequence (PRBS) Signal. Two correlation coefficients are calculated that can be interpreted, together, as a measure that determines whether the channel is WSS or not. A similar wide-sense stationarity assessment can be performed on the basis of the Time-Varying Impulse Response (TVIR) of a UAC channel. However, the method proposed in this paper requires fewer computational operations in the receiver of a UAC system. PRBS Signal transmission tests were conducted in the UAC channel simulator and in real conditions during an inland water experiment. The correlation coefficient values obtained using the method based on the envelope of a Probe Signal and the method of analysing the TVIR estimates are compared. The results are similar, and thus, it is possible to assess if the UAC channel can be modelled as a WSS stochastic process without the need for TVIR estimation.

  • Estimation of Coherence Bandwidth for Underwater Acoustic Communication Channel
    2018 Joint Conference - Acoustics, 2018
    Co-Authors: Iwona Kochanska, J. Schmidt
    Abstract:

    A shallow underwater acoustic communication channel is characterized by strong multipath propagation. The Signal reaching the receiver consists of a direct waveform and a number of its delayed and suppressed replica. A significant time dispersion of the transmitted Signal and selective fading of its spectrum are observed. Coherence bandwidth defines maximal bandwidth, wherein the channel amplitude characteristic remains constant and its phase characteristic is linear. It is one of the channel transmission parameters that determine the physical layer of data transmission. Coherence bandwidth can be calculated on the basis of the channel impulse response, measured by the correlation method with the use of wideband frequency modulated Signals or pseudo-random binary sequences. Both types of Probe Signals have an impulse-like autocorrelation function whose influence on the impulse response estimate is often considered as negligible. However, Probe Signals practically used in measuring systems have a limited bandwidth, which causes their correlation properties to be different than in the truly wideband case. This has a direct impact on impulse response and transmission parameters estimates. In particular, the coherence bandwidth can differ significantly depending on the Probe Signal used. The paper proposes a method of correction of the Probe Signal influence on the estimate of channel coherence bandwidth.

  • Probe Signal processing for channel estimation in underwater acoustic communication system
    Signal Processing: Algorithms Architectures Arrangements and Applications, 2017
    Co-Authors: Iwona Kochanska, J. Schmidt
    Abstract:

    Underwater acoustic communication channels are characterized by a large variety of propagation conditions. Designing a reliable communication system requires knowledge of the transmission parameters of the channel, namely multipath delay spread, Doppler spread, coherence time, and coherence bandwidth. However, the possibilities of its estimation in a real-time underwater communication system are limited, mainly due to the computational time of implementations of the digital Signal processing algorithms. The article presents the results of analysis of Probe Signals measured during a shallow water experiment. The implementation issues of estimation algorithms are discussed, assuming floating point arithmetic, and with both single-core and multi-core digital Signal processors as the target platforms.

  • SPA - Probe Signal processing for channel estimation in underwater acoustic communication system
    2017 Signal Processing: Algorithms Architectures Arrangements and Applications (SPA), 2017
    Co-Authors: Iwona Kochanska, J. Schmidt
    Abstract:

    Underwater acoustic communication channels are characterized by a large variety of propagation conditions. Designing a reliable communication system requires knowledge of the transmission parameters of the channel, namely multipath delay spread, Doppler spread, coherence time, and coherence bandwidth. However, the possibilities of its estimation in a real-time underwater communication system are limited, mainly due to the computational time of implementations of the digital Signal processing algorithms. The article presents the results of analysis of Probe Signals measured during a shallow water experiment. The implementation issues of estimation algorithms are discussed, assuming floating point arithmetic, and with both single-core and multi-core digital Signal processors as the target platforms.

J. Schmidt - One of the best experts on this subject based on the ideXlab platform.

  • Estimation of Coherence Bandwidth for Underwater Acoustic Communication Channel
    2018 Joint Conference - Acoustics, 2018
    Co-Authors: Iwona Kochanska, J. Schmidt
    Abstract:

    A shallow underwater acoustic communication channel is characterized by strong multipath propagation. The Signal reaching the receiver consists of a direct waveform and a number of its delayed and suppressed replica. A significant time dispersion of the transmitted Signal and selective fading of its spectrum are observed. Coherence bandwidth defines maximal bandwidth, wherein the channel amplitude characteristic remains constant and its phase characteristic is linear. It is one of the channel transmission parameters that determine the physical layer of data transmission. Coherence bandwidth can be calculated on the basis of the channel impulse response, measured by the correlation method with the use of wideband frequency modulated Signals or pseudo-random binary sequences. Both types of Probe Signals have an impulse-like autocorrelation function whose influence on the impulse response estimate is often considered as negligible. However, Probe Signals practically used in measuring systems have a limited bandwidth, which causes their correlation properties to be different than in the truly wideband case. This has a direct impact on impulse response and transmission parameters estimates. In particular, the coherence bandwidth can differ significantly depending on the Probe Signal used. The paper proposes a method of correction of the Probe Signal influence on the estimate of channel coherence bandwidth.

  • Probe Signal processing for channel estimation in underwater acoustic communication system
    Signal Processing: Algorithms Architectures Arrangements and Applications, 2017
    Co-Authors: Iwona Kochanska, J. Schmidt
    Abstract:

    Underwater acoustic communication channels are characterized by a large variety of propagation conditions. Designing a reliable communication system requires knowledge of the transmission parameters of the channel, namely multipath delay spread, Doppler spread, coherence time, and coherence bandwidth. However, the possibilities of its estimation in a real-time underwater communication system are limited, mainly due to the computational time of implementations of the digital Signal processing algorithms. The article presents the results of analysis of Probe Signals measured during a shallow water experiment. The implementation issues of estimation algorithms are discussed, assuming floating point arithmetic, and with both single-core and multi-core digital Signal processors as the target platforms.

  • SPA - Probe Signal processing for channel estimation in underwater acoustic communication system
    2017 Signal Processing: Algorithms Architectures Arrangements and Applications (SPA), 2017
    Co-Authors: Iwona Kochanska, J. Schmidt
    Abstract:

    Underwater acoustic communication channels are characterized by a large variety of propagation conditions. Designing a reliable communication system requires knowledge of the transmission parameters of the channel, namely multipath delay spread, Doppler spread, coherence time, and coherence bandwidth. However, the possibilities of its estimation in a real-time underwater communication system are limited, mainly due to the computational time of implementations of the digital Signal processing algorithms. The article presents the results of analysis of Probe Signals measured during a shallow water experiment. The implementation issues of estimation algorithms are discussed, assuming floating point arithmetic, and with both single-core and multi-core digital Signal processors as the target platforms.

Julie E Greenberg - One of the best experts on this subject based on the ideXlab platform.

  • analysis of speech based speech transmission index methods with implications for nonlinear operations
    Journal of the Acoustical Society of America, 2004
    Co-Authors: Raymond L Goldsworthy, Julie E Greenberg
    Abstract:

    The Speech Transmission Index (STI) is a physical metric that is well correlated with the intelligibility of speech degraded by additive noise and reverberation. The traditional STI uses modulated noise as a Probe Signal and is valid for assessing degradations that result from linear operations on the speech Signal. Researchers have attempted to extend the STI to predict the intelligibility of nonlinearly processed speech by proposing variations that use speech as a Probe Signal. This work considers four previously proposed speech-based STI methods and four novel methods, studied under conditions of additive noise, reverberation, and two nonlinear operations (envelope thresholding and spectral subtraction). Analyzing intermediate metrics in the STI calculation reveals why some methods fail for nonlinear operations. Results indicate that none of the previously proposed methods is adequate for all of the conditions considered, while four proposed methods produce qualitatively reasonable results and warrant ...

  • analysis of speech based speech transmission index methods with implications for nonlinear operations
    Journal of the Acoustical Society of America, 2004
    Co-Authors: Raymond L Goldsworthy, Julie E Greenberg
    Abstract:

    The Speech Transmission Index (STI) is a physical metric that is well correlated with the intelligibility of speech degraded by additive noise and reverberation. The traditional STI uses modulated noise as a Probe Signal and is valid for assessing degradations that result from linear operations on the speech Signal. Researchers have attempted to extend the STI to predict the intelligibility of nonlinearly processed speech by proposing variations that use speech as a Probe Signal. This work considers four previously proposed speech-based STI methods and four novel methods, studied under conditions of additive noise, reverberation, and two nonlinear operations (envelope thresholding and spectral subtraction). Analyzing intermediate metrics in the STI calculation reveals why some methods fail for nonlinear operations. Results indicate that none of the previously proposed methods is adequate for all of the conditions considered, while four proposed methods produce qualitatively reasonable results and warrant further study. The discussion considers the relevance of this work to predicting the intelligibility of cochlear-implant processed speech.

Jean Christophe Cousin - One of the best experts on this subject based on the ideXlab platform.

  • high resolution estimation for time variant mimo channel sounding
    Transactions on Emerging Telecommunications Technologies, 2008
    Co-Authors: Sofia Martinez Lopez, Judson A Braga, B Huyart, Jean Christophe Cousin
    Abstract:

    A wideband vector channel sounder with 16 parallel RF chains is proposed for parameter estimation in an indoor channel. Low-cost and high-resolution are obtained by using a chirp Probe Signal, five-port receivers and the MUSIC algorithm. The system covers up to 500 MHz centred at 2.45 GHz. Experimental results show errors inferior to 1 ns in the time domain and of few degrees in the angular domain. Accurate results are found in static as well as in time-variant scenarios. Copyright © 2008 John Wiley & Sons, Ltd.

  • high resolution estimation for time variant mimo channel sounding
    European Wireless Conference, 2008
    Co-Authors: Sofia Martinez Lopez, Judson A Braga, B Huyart, Jean Christophe Cousin
    Abstract:

    A wideband vector channel sounder with 16 parallel RF chains is proposed for parameter estimation in an indoor channel. Low-cost and high-resolution are obtained by using a chirp Probe Signal, five-port receivers and the MUSIC algorithm. The system covers up to 500 MHz centred at 2.45 GHz. Experimental results show errors inferior to 1 ns in the time domain and of few degrees in the angular domain. Accurate results are found in static as well as in time-variant scenarios.

Raymond L Goldsworthy - One of the best experts on this subject based on the ideXlab platform.

  • analysis of speech based speech transmission index methods with implications for nonlinear operations
    Journal of the Acoustical Society of America, 2004
    Co-Authors: Raymond L Goldsworthy, Julie E Greenberg
    Abstract:

    The Speech Transmission Index (STI) is a physical metric that is well correlated with the intelligibility of speech degraded by additive noise and reverberation. The traditional STI uses modulated noise as a Probe Signal and is valid for assessing degradations that result from linear operations on the speech Signal. Researchers have attempted to extend the STI to predict the intelligibility of nonlinearly processed speech by proposing variations that use speech as a Probe Signal. This work considers four previously proposed speech-based STI methods and four novel methods, studied under conditions of additive noise, reverberation, and two nonlinear operations (envelope thresholding and spectral subtraction). Analyzing intermediate metrics in the STI calculation reveals why some methods fail for nonlinear operations. Results indicate that none of the previously proposed methods is adequate for all of the conditions considered, while four proposed methods produce qualitatively reasonable results and warrant ...

  • analysis of speech based speech transmission index methods with implications for nonlinear operations
    Journal of the Acoustical Society of America, 2004
    Co-Authors: Raymond L Goldsworthy, Julie E Greenberg
    Abstract:

    The Speech Transmission Index (STI) is a physical metric that is well correlated with the intelligibility of speech degraded by additive noise and reverberation. The traditional STI uses modulated noise as a Probe Signal and is valid for assessing degradations that result from linear operations on the speech Signal. Researchers have attempted to extend the STI to predict the intelligibility of nonlinearly processed speech by proposing variations that use speech as a Probe Signal. This work considers four previously proposed speech-based STI methods and four novel methods, studied under conditions of additive noise, reverberation, and two nonlinear operations (envelope thresholding and spectral subtraction). Analyzing intermediate metrics in the STI calculation reveals why some methods fail for nonlinear operations. Results indicate that none of the previously proposed methods is adequate for all of the conditions considered, while four proposed methods produce qualitatively reasonable results and warrant further study. The discussion considers the relevance of this work to predicting the intelligibility of cochlear-implant processed speech.